Optical reading device with programmable led control

ABSTRACT

An apparatus comprising: a sensor array having rows of pixels which are exposed to symbol indicia, wherein the sensor array generates a sync signal; an aiming pattern generator for producing an aiming pattern superimposed on the symbol indicia; a processor which utilizes the sync signal to control the aiming pattern generator to: turn on the aiming pattern during exposure of a first predetermined row of pixels; turn off the aiming pattern during exposure of a second predetermined row of pixels; turn on the aiming pattern during exposure of a third predetermined row of pixels; and, a housing for housing the sensor array, aiming pattern generator and processor for hand held operation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority of copendingU.S. patent application Ser. No. 11/405,964 filed Apr. 18, 2007,entitled “Optical Reading Device with Programmable LED Control.” Thepriority of the above application is claimed, and the disclosure of theabove application is incorporated herein by reference in its entirety.

This application is a continuation-in-part of and claims priority ofco-pending U.S. patent application Ser. No. 10/842,851 filed May 11,2004, entitled “Picture Taking Optical Reader.” The priority of theabove application is claimed, and the disclosure of the aboveapplication is incorporated herein by reference in its entirety, whichapplication claims priority of Provisional Application No. 60/470,016filed May 12, 2003, entitled “Picture Taking Optical Reader.” Thepriority of the above application is claimed, and the disclosure of theabove application is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to optical reading devices, and moreparticularly to an optical reading device having programmable aimerand/or illumination control.

BACKGROUND

Optical reading devices typically read data represented by symbols. Forinstance a bar code symbol is an array of rectangular bars and spacesthat are arranged in a specific way to represent elements of data inmachine readable form. Optical reading devices typically transmit lightonto a symbol and receive light reflected off of the symbol. Thereceived light is interpreted by an image processor to extract the datarepresented by the symbol.

One-dimensional (1D) optical bar code readers are characterized byreading data that is encoded along a single axis, in the widths of barsand spaces, so that such symbols can be read from a single scan alongthat axis, provided that the symbol is imaged with a sufficiently highresolution along that axis.

In order to allow the encoding of larger amounts of data in a single barcode symbol, a number of 1D stacked bar code symbologies have beendeveloped which partition encoded data into multiple rows, eachincluding a respective 1D bar code pattern, all or most all of whichmust be scanned and decoded, then linked together to form a completemessage. Scanning still requires relatively high resolution in onedimension only, but multiple linear scans are needed to read the wholesymbol.

A class of bar code symbologies known as two dimensional (2D) matrixsymbologies have been developed which offer orientation-free scanningand greater data densities and capacities than 1D symbologies. 2D matrixcodes encode data as dark or light data elements within a regularpolygonal matrix, accompanied by graphical finder, orientation andreference structures. When scanning 2D matrix codes, the horizontal andvertical relationships of data elements are recorded with about equalresolution.

Often times a bar code reader may be portable and wireless in naturethereby providing added flexibility. In these circumstances, suchportable bar code readers form part of a wireless network in which datacollected within the terminals is communicated to a host computersituated on a hardwired backbone via a wireless link. For example, theportable bar code readers may include a radio or optical transceiver forcommunicating with a host computer via a base station.

Conventionally, a bar code reader, whether portable or otherwise,includes a central processor which directly controls the operations ofthe various electrical components housed within the bar code reader. Forexample, the central processor controls detection of keyboard entries,display features, wireless communication functions, trigger detection,and bar code read and decode functionality.

Efforts regarding such systems have led to continuing developments toimprove their versatility, practicality and efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary partially cutaway side view of a reader whichhas an optics unit and an aiming pattern generator in accordance withthe invention.

FIG. 2 is a side view of an optics assembly in accordance with theinvention.

FIG. 3 is a block schematic diagram of an optical reader in accordancewith the invention.

FIG. 4 is flow chart for operating an optical reader system inaccordance with the invention.

FIG. 5 a is a schematic diagram of an imager processor in accordancewith the present invention.

FIG. 5 b is a schematic diagram of a aimer and illumination controlcircuit in accordance with the present invention.

FIG. 6 is a schematic diagram of a laser aimer control circuit inaccordance with the present invention.

FIG. 7 is a diagram of an optical reader in accordance with the presentinvention.

FIG. 8 a illustrates the operation of an image sensor employing arolling shutter architecture in accordance with the present invention.

FIG. 8 b is a timing diagram used in the rolling shutter architecturepresented with respect to FIG. 8 a.

FIG. 9 is a block electrical diagram and timing circuit for image sensorin accordance with the present invention.

FIGS. 10 a and 10 b are flow charts of processes for collecting imagedata in accordance with the invention.

FIG. 11 is a block diagram of an image sensor in accordance with thepresent invention.

FIG. 12 is a flow chart of a process for collecting image data inaccordance with the invention.

FIG. 13 is a timing diagram used in the global shutter architecture inaccordance with the invention.

FIG. 14 is a diagram of an image sensor in accordance with the presentinvention.

DETAILED DESCRIPTION

Reference will now be made to exemplary embodiments of the inventionwhich are illustrated in the accompanying drawings. This invention,however, may be embodied in various forms and should not be construed aslimited to the embodiments set forth herein. Rather, theserepresentative embodiments are described in detail so that thisdisclosure will be thorough and complete, and will fully convey thescope, structure, operation, functionality, and potential ofapplicability of the invention to those skilled in the art. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

An optical reader in accordance with the invention may be adapted forreading symbol indicia for numerous functions. A detailed description oftransaction terminals and their operation is disclosed in commonly ownedpublished United States Patent Application Publication No. 20030029917entitled OPTICAL READER FOR IMAGING MODULE, which is hereby incorporatedherein in it's entirety.

The description of the optical reader in said publication is broken downinto the eight subheadings:General Imaging Module Architectures andAssembly; Illumination Systems; Aiming Systems, Illumination DeviceArchitectures; Illumination/Aiming Color Emission Control andCoordination; Receive Optics, Packaging of Electronics; andApplications, Operating Environment, and Control Circuit Functionality.

Block diagrams of electrical circuit control configurations which may bewholly or partially incorporated in reader 10 or used in combinationwith circuitry of reader 10 are now described.

Referring to FIGS. 1 and 2, there is shown an enlarged fragmentarycross-sectional view of an optical reader 111 constructed in accordancethe invention. Reader 111 includes a low profile imaging assembly 112which includes a 2D imager or imaging subassembly 143, a lens or imagingoptics subassembly 138 and an aiming pattern generator or subassembly155. The latter subassemblies are obscured in FIG. 1 by a single pieceor monolithic mounting/retaining structure 130 which supports, separatesand encloses the same. This mounting structure is provided with holesthrough which may be passed the screws (not shown) which hold opticsunit 112 together as a complete compact scanning assembly or engine.

Aiming illumination pattern generator 155 is adapted to generate a 2Daiming pattern which is defined, and aligned or coincident with thefield of view of imaging subassembly 143. A number of representative 2Daiming patterns are possible and not limited to any particular patternor type of pattern, such as any combination of rectilinear, linear,circular, elliptical, etc. figures, whether continuous or discontinuous,i.e., defined by sets of discrete dots, dashes and the like.

To this end, the patterns may be generated by an aiming patterngenerator 155 which takes the form of a module or cartridge oneembodiment of which is shown in assembled, cross-sectional form in FIG.2. Aiming generator 155 may include a point-like light source, such as alaser diode or resonant cavity LED, an aiming optics assembly, andinterference pattern generating device which are together adapted to fitinto an appropriately shaped receiving cavity defined by a mountingmember.

The light source of aiming generator 155 may comprise a surface emittingvisible laser diode such as those available from Rohm, or a non-laserlight source such as a light emitting diode (LED). More generally, thelight source may comprise any light source which is sufficiently smallto approximate a thin source and sufficiently bright to provide thedesired intensity illumination at the target. Coherency of the light isnot essential for purposes of the present invention.

To the end, a collimated light beam may be used to generate an aimingpattern of the desired type and shape, aiming pattern generator 155 mayinclude an interference pattern generating element, such as aholographic element, diffractive optic element that includes one or morediffractive gratings, or a Fresnel type optic element which has beenfabricated with the desired pattern in mind. Examples of each of thesetypes of elements are known, commercially available items and may bepurchased, for example, from Digital Optics Corp. of Charlotte, N.C.among others. Elements of some of these types and methods for makingthem are also described in U.S. Pat. Nos. 4,895,790 (Swanson); 5,170,269(Lin et al) and 5,202,775 (Feldman et al), which are hereby incorporatedherein by reference. Accordingly, the structure and operation of thesedevices will be described only generally herein.

Referring to the block diagram of FIG. 3, an imaging device processorassembly 14 a includes an illumination assembly 121 for illuminating atarget area T, such as a substrate bearing a 1D or 2D bar code symbol ora text string or other machine readable indicia, and an imaging assembly133 for receiving an image of object T and generating an electricaloutput signal indicative of the data optically encoded therein.Illumination assembly 121 may, for example, include an illuminationsource assembly e.g. LED power supply 123, Aimer power supply 122, LEDs16, 18, together with an illuminating optics assembly 124, such as oneor more lenses 25, diffusers 27, wedges 28, reflectors 640 or acombination of such elements, for directing light from light source 16,18 in the direction of a target object T. The Illumination source may belocated off-axis such as by locating it a distance from the imagingassembly or external to the reader. Illumination assembly 121 maycomprise, for example, laser or light emitting diodes 16, 18 (LEDs) suchas white, green or red LEDs. Illumination assembly 121 may includetarget illumination optics for projecting an aiming pattern e.g. 630,631, 647 on target T. Illumination assembly 121 may be eliminated ordisabled if ambient light levels are certain to be high enough to allowhigh quality images of object T to be taken. Illumination assembly 121may also be located remote from imaging device housing 111, at alocation so as to eliminate or reduce specular reflections. Imagingassembly 133 may include an image sensor 32, such as a color ormonochrome 1D or 2D CCD, CMOS, NMOS, PMOS, CID or CMD solid state imagesensor, together with an imaging optics assembly 40 for receiving andfocusing an image of object T onto image sensor 32. CMOS based imagesensors contain arrays of light sensitive photodiodes (or pixels) thatconvert incident light energy into electric charge. CMOS based imagesensors allow each pixel in a two-dimensional array to be directlyaddressed, so that sub-regions of a full frame of image data can beindependently accessed.

In another example, imaging assembly 133′ may include image sensor 32,processors 135, 150, and ND 136. To this end, one or more of thesecomponents may be combined into a single chip or integrated circuit.

Features and advantages associated with incorporating a color imagesensor in an imaging device, and other control features which may beincorporated in a control circuit are discussed in greater detail inU.S. Pat. No. 6,832,725 entitled “An Optical Reader Having a ColorImager” incorporated herein by reference. The array-based imagingassembly may be replaced by a laser array based imaging assemblycomprising one or more laser sources, a scanning mechanism, emit andreceive optics, at least one photodetector and accompanying signalprocessing circuitry. It is to be noted that the image sensor 32 mayread images without the illumination from illumination assembly 121,such as by ambient light.

Imaging device processor assembly 14 a may include a programmablecontrol circuit or imager processor 150. Imager processor 150 controlsthe amount of illumination provided by LEDs 16, 18 by controlling theoutput power provided by LED power supply 19. Imager processor 150 mayalso control other functions and devices of the imager. Image processormay be a CY8C24223A made by Cypress Semiconductor Corporation, which isa Mixed-Signal Array with On-Chip Controller devices designed to replacemultiple traditional MCU-based system components with one single-chipprogrammable device. The processor may include configurable blocks ofanalog and digital logic, as well as programmable interconnects.Processor 150 includes a predetermined amount of memory 152 for storingdata.

The components in imaging device processor assembly 14 a may beconnected by bus 192, such as an Inter-IC bus such as an I²C bus, whichis a control bus that provides a communications link between integratedcircuits in a system. Typically this bus would connect to a hostcomputer in relatively close proximity, but not necessarily on the sameprinted circuit board as used by the imaging device processor assembly14 a. I²C is a two-wire serial bus with a software-defined protocol andused to link components such as the image sensor 32, temperaturesensors, voltage level translators, EEPROMs, general-purpose I/O, AIDand D/A converters, CODECs, and microprocessors.

The functional operation of the host processor 193 involves theperformance of a number of related steps, the particulars of which maybe determined by or based upon certain parameters, some or all of whichmay be stored in memory 152 provided as part of the imager processor150. Included among these steps is a scanning subroutine which specifiesthe address buffer space or spaces in which scan data will be stored andwhether scanning is to be continuous (e.g., at a full video rate, suchas 30 frames per second), or discontinuous (e.g., with pauses related tothe current state of the trigger). The operation of the decodingroutine, which is executed in a user or factory selectable relationshipto the scanning routine, is governed by parameters which control thecodes which are enabled for processing as a part of anautodiscrimination process, whether decoding is to be continuous ordiscontinuous, etc. Permitted combinations of scanning and decodingparameters together define the scanning-decoding relationships or modeswhich the reader will use.

Memory 152 may also be used to store other parameters. For example, thedecoder functions best if it knows the aiming pattern 74 centercoordinates or other position in order to decode the symbol that isclosest to the aiming center parameter, or the symbol that is in someposition relative to the aiming center. The aiming center is based on anumber of mechanical tolerances and will generally be different forevery device produced. One could choose a center coordinate based on astatistical sampling of data, but the center may move over time as themanufacturing process is changed. The aiming center x- and y-coordinatecan be measured during the manufacturing process and stored in theprocessor memory 152. The distance D at which the measurement was mademay also be stored. One could measure the coordinates at two differentdistances and then apply a mathematical translation to determine whatthe coordinates would be at a third distance. The center coordinates andthe distance could be read out at a later point in time. Knowledge ofaimer location may be used for turning the aiming pattern on and off asis described herein.

During the manufacture of a scanner, the different tolerances of thedifferent parts have a tendency to “stack up”, or add together. Such atolerance stack may result in problematic performance. For instance, itmay lead to a situation where the aimer pattern 74 does not intersectthe center pixel area of the sensor 32. This misalignment due totolerance will give poor results unless such an aiming pattern “offset”is compensated for by the signal processor in a calibration step.Storing the aiming pattern offset or position in the processor memorywill facilitate such calibration at future times, such as repairs orcustomer locations. Aimer pattern location may also be used incontrolling the aimer on and off during exposure of the image sensor.

Another exemplary parameter to be stored for the scan driver to utilizeis the type of aiming system that is employed in order to control theaimer. Examples of aiming systems are LED and laser aimer options, whichmay require different control methods.

Another exemplary parameter to be stored is image module, engine partnumber or serial number, or other manufacturing specific informationwhich may be used for a number of tracking purposes, such as softwarecontrol, sales tracking or warranty tracking.

Another exemplary parameter to be stored is the number of pixels in theimage to be used for initializing buffers and for software control.

Another exemplary parameter to be stored is the orientation that theengine will be mounted in its final implementation for decodingalgorithms that are direction-dependent, or for ensuring that images aredisplayed and stored in the proper orientation from the operator's pointof view.

Another exemplary parameter to be stored is information about the fieldillumination flatness of the engine with and without on-boardillumination activated, for instance for purposes of applyingcompensation algorithms that either improve decoding or improve thevisual quality of the image. Field illumination flatness may be definedas a profile saved as a function of radius from the imager opticalcenterline.

Another exemplary parameter to be stored is information regarding lensdistortions across the active image field that may be used to improvedecoding or to improve the visual quality of the image.

Other exemplary parameters to be stored may include dead or bad pixelidentification for image correction, noise characterization of the imagesensor so that the image algorithms can correct for and functionappropriately.

Other exemplary parameters to be stored may include max LED current andreceiving lens prescription or parameters functionally related thereto.

Another exemplary parameter to be stored is information regarding aparameter representative of the operative power output of the laserdiode aiming system, such as operating current or a parameter related tothe operating current.

In the present invention for instance, if the image scan engine 110, 110a is replaced, the scanner has the ability to automatically read outcertain parameter information in processor memory and can thus sensewhen an engine has been replaced and allow the software to adapt and usedifferent methods of control, or different methods of decoding, ordifferent methods of displaying and saving images, etc.

Another exemplary application for the present invention is to comparerun time parameter data of the image scan engine with the storedparameters for diagnostic evaluation. This may be done locally orremotely by connecting the optical reader either directly or through anetwork 194 (such as the internet) to a remote network computer 171 andhaving the network computer provide appropriate diagnostics.

Another exemplary application for the present invention is to storeinformation about the scanner capabilities, such as whether the imageris enabled for image capture, what type of decoder level is enabled, orwhat types of symbology decoding is enabled. To this end, the user mayupdate or replace one or more stored parameters or parameter datautilizing a remote updating system. This may be done by connecting theoptical reader either directly or through a network 194 (such as theinternet) to a remote network computer 171. With the appropriatesoftware, the network computer can be programmed to read certainparameters from the optical reader, such as software configuration. Thenetwork computer 171 could read the parameter data and utilize that datafor downloading updates or new software. For instance, an operator mayrequest from the network computer for a software update. The requestwould be received by either computer, which could read the currentsoftware configuration resident on the optical reader and determine theappropriate update or replacement software.

An operator may have the ability to acquire through a purchase orotherwise new or updated software following the flow chart provided inFIG. 4. In a step 920 an optical reader is connected to a networkcomputer. In a step 924, the network computer reads the optical readerconfiguration/data parameters from memory. In a step 928, the operatorrequests from the network computer a software update/replacementdownload from the network computer. In a step 932, the network computerverifies the optical reader is compatible with the software request.This may entail such things as verifying optical reader has requisitehardware or software, or verifying the operator has fulfilled certaincontractual obligations, such as making appropriate payments or agreeingto contractual terms. If the reader is compatible, the software can bedownloaded in a step 936. If not, the operator is notified in a step940. The network computer may host a website on the internet utilizingHTML technology for providing the interface for the software download.Other interfaces and systems may also be utilized. The processor 150 maytherefore be programmed to update the data and software utilizing aremote updating system.

FIGS. 5 a-b, are schematics of an imager processor 150 and LED controlcircuit 123 for an optical reading device in accordance with the presentinvention. It can be seen that imager processor 150 controls the powerto the illumination LEDs via a line ILL_CTL and the power to the aimerLEDs via a line AIM_CTL. Feedback for the amount of LED current isprovided on a line LED_CURRENT. Through the control lines ILL_CTL andAIM_CTL, the image field illumination and aiming pattern illuminationcan be independently controlled.

An example of a laser aimer power supply 122 circuit is shown in FIG. 6.

An embodiment in accordance with the present invention is shown in FIG.7, which is similar to that shown in FIG. 3 except that memory 152 isnot part of or integral with the imager processor 150. The imagerprocessor 150 may be located remotely from imager printed circuit board(PCB) 14 a, or imager assembly 10, or optical reader 114 k. If so,memory device 152 may be located on the PCB for storing theaforementioned parameters. The bus 192 may still be utilized for datatransfer on the imager PCB. An alternate connection might also beutilized for communication between the imager processor 150 and theimager PCB. A configuration with only the memory and not the processoron the PCB facilitates a smaller optical reader package. It is to benoted that imager processor 150 and host processor 193 may be a singleintegrated circuit or separate processors disposed on a single printedcircuit board.

As herein described, image sensor 32 may comprise a two-dimensional CMOSbased image sensor array. The illumination LEDs shine light on thetarget so that reflected light can be collected and processed by theimage sensor array. The Aimer LEDs shine light on the target to aid anoperator of the image reader to accurately aim the reader at the target.

The CMOS sensor array may employ a “rolling shutter” architecture toexpose the pixels, wherein rows of pixels are activated or exposed andread in sequence. The exposure or integration time for a pixel is thetime between a pixel being reset and its value being read-out. Thisconcept is presented in FIG. 8 a. In FIG. 8 a, the exposure for each ofthe rows “R_(a)” though “R_(n)” is diagrammatically represented by thebars a . . . n. The horizontal extent EP of each bar is intended tocorrespond to the exposure period for a particular row. The horizontaldisplacement of each bar is suggestive of the shifting time periodduring which each row of pixels is exposed. This is shown in more detailwith respect to the timing diagrams for a rolling shutter architectureshown in FIG. 8 b. The second line of the timing diagram represents arow exposure timing signal 330 pulse train. The third line represents arow readout timing signal 332 pulse train. These timing signals aregenerated by the image sensor 32. As shown in both FIGS. 8 a and 8 b,the exposure for row “b” is initiated before the values for row “a” areread-out. The exposure periods for adjacent rows of pixels typicallyoverlap substantially as several hundred rows of pixels must be exposedand read during the capture of a frame of data. As shown by theillumination timing signal on the first line, the rolling shutterarchitecture with its overlapping exposure periods requires that theillumination source remain on during substantially all of the timerequired to capture a frame of data so that illumination is provided forall of the rows. In this manner the optical reader reads symbol indiciaand produces digital symbol image data representative of the symbolindicia, the digital symbol image data being comprised of pixelssystematized into rows wherein each pixel has a digital value.

An exemplary image reader 110 is described with reference to FIG. 9,wherein a two-dimensional array of pixels is incorporated onto CMOSimage sensor array adapted to operate in a global shutter operatingmode. Row circuitry and the column circuitry may enable one or morevarious processing and operational tasks such as addressing pixels,decoding signals, amplification of signals, analog-to-digital signalconversion, applying timing, read-out and reset signals and the like.

The time during which the target is illuminated is referred to as theillumination period. The time during which the aimer LEDs are on isreferred to as the aiming period. The time during which the pixels arecollectively activated to photo-convert incident light into chargedefines the exposure period for the sensor array. The exposure periodfor each row is controlled by a timing signal referred to as a rowexposure timing signal. At the end of the exposure period, collectedcharge is read out.

The timing of the exposure period and the illumination period may beunder the control of the control module or imager processor 152, whichcauses at least a portion of the exposure period to occur during theillumination period. The imager processor also organizes and processesthe reading out of data from the sensor array in a rolling shutter modecapable of sequentially exposing and reading out the lines of pixels inthe image sensor array. The time during which the pixels arecollectively activated to photo-convert incident light into chargedefines the exposure period for the sensor array. At the end of theexposure period, the collected charge is transferred to a shieldedstorage area until the data is read out. Imager processor 152 controlsthe process to collect the pixel matrix information utilizing anillumination signal and a row reset signal. The illumination (orbeginning of frame) signal indicates the beginning of data collectionfor the frame F (pixel matrix). Among other things, the imager processor152 uses this signal to know when the image capture begins and ends withthe complete frame or image being stored in system memory. The rowexposure timing signal is a train of pulses used to time the collectionof data for each row R_(a)-R_(n) (or data block) in the frame. Imagerprocessor 152 generates an aimer control signal (AIM_CTL) to turn theaimer LEDs on and off.

An aspect of the present invention is to control the on/off sequence ofthe illumination of the aiming pattern so that the aiming pattern isturned off during predetermined times of image collection, such as whendata is being collected from the pixel matrix in areas where the aimingpattern is being projected or superimposed onto the target. It may bedesirable to produce a digital image of the target without the aimingpattern superimposed on the picture. A technique which may be utilizedto accomplish this objective is to use the row read-out pulses tocalculate when data is being collected in the pixel matrix rows thatinclude the superimposed aiming pattern. For example as shown in FIG. 8,the aiming pattern might be imposed in the frame F in the fourth andfifth rows R_(d) and R_(e). Data from the matrix is collectediteratively from each consecutive row during each consecutive rowreadout pulse. The aiming pattern might thus be turned off by countingthe number of row exposure pulses after the illumination sync pulse, andturning off the aiming pattern at the appropriate row coinciding withthe respective row readout pulse count, and then turning on the aimingpattern at the appropriate row coinciding with the respective rowreadout pulse count. So for the example in FIG. 9, it can be seen thatthe aiming pattern AP may be turned off to coincide with the third rowexposure pulse occurring after the beginning illumination sync pulse BOF(beginning of frame) and turned back on at the leading edge of the sixthrow exposure pulse occurring after the beginning illumination sync pulseBOF. Since the position of the aiming pattern within the frame is known,the appropriate row exposure pulse counts are known and may be stored inthe imager processor memory 152 to be utilized for such aiming patternon-off control. The frame illustrated in FIG. 9 is for example only.Typically, an image capture frame would consist of more pixel rows andcolumns than that shown.

FIG. 10 a is a flow chart depicting the aiming pattern operation. Aillumination sync pulse is generated to begin image capture of the framein a step 710. A row exposure pulse train is then generated in a step712. The image pixel data from each row is iteratively collectedcoincident with the following row exposure pulses. Each row exposurepulse is counted by the imager processor 150 and a query is made in astep 714 to determine when the appropriate row is encountered (in theexample of FIG. 9, the fourth row) where the aiming pattern resides.When the appropriate row exposure pulse (i.e. row number) is reached,the aimer is turned off in a step 716. The aimer remains off until, in aquery in step 718, the next appropriate row number is reached (in theexample of FIG. 9, the sixth row), at which time the aimer may be turnedback on in a step 720. In this manner, the aimer pattern will not beincluded in the pixel data collected in rows R_(d) and R_(e). It is tobe noted that other rows before and after the aiming pattern may bechosen as the predetermined signal switching rows to, for example,provide a wider tolerance to ensure the aiming pattern is turned off andon outside of the image capture frame coincident with the rowssuperimposed with the aiming pattern. Also, as noted previously, otheraiming patterns may be utilized.

Alternatively, the aimer may be left on for a predetermined amount oftime after a predetermined row exposure pulse.

Also, the aimer may be controlled utilizing any of a number of syncsignals or pulses provided by the image sensor for providing informationwith regard to when pixel data is available for read out. For instance,in addition to the exposure sync signal, the vertical sync signal(Vsync) the horizontal sync signal (Hsync), the pixel clock signal(Pixel clock), etc.

FIG. 10 b is a flow chart depicting the aiming pattern operation. Aillumination sync pulse is generated to begin image capture of the framein a step 710′. A row exposure pulse train is then generated in a step712′. The image pixel data from each row is iteratively collectedcoincident with the following row exposure pulses. Time is counted bythe imager processor 150 and a query is made in a step 714′ to determinewhether a first predetermined amount of time has elapsed. When theappropriate time is reached, the aimer is turned off in a step 716′. Theaimer remains off until, in a query in step 718′, for a secondpredetermined amount of time at which time the aimer may be turned backon in a step 720′. In this manner, the aimer pattern will not beincluded in the pixel data collected in rows R_(d) and R_(e). It is tobe noted that other rows before and after the aiming pattern may bechosen as the predetermined signal switching rows to, for example,provide a wider tolerance to ensure the aiming pattern is turned off andon outside of the image capture frame coincident with the rowssuperimposed with the aiming pattern. Also, as noted previously, otheraiming patterns may be utilized.

The image reader may be capable of operating in either the rollingshutter mode or a global electronic shutter mode. In the globalelectronic shutter operational mode, the image reader 32 collects a fullframe of image data wherein all image reader pixels are exposed nearlysimultaneously and the data is stored and subsequently processed to, forexample, decode a barcode contained in the image data.

A process 300 for collecting target image data in the global electronicshutter operational mode is presented with respect to FIGS. 12, 13, and14 and includes projecting (step 302) an aiming pattern on the target inresponse to an aimer control timing pulse 320. The aiming patternappears on the target the duration of the aimer control timing pulse.The aiming pattern is then deactivated in a step 304. In a step 306 anillumination source illuminates the target in response to anillumination control timing pulse 322. Illumination of the target occursfor the duration of the illumination control timing pulse 322. Theprocess 300 also includes simultaneously activating (step 308) aplurality of pixels in a plurality of rows in an image sensor array tophotoconvert incident radiation into electric charge. The simultaneousactivation of the plurality of pixels occurs in response to an exposurecontrol timing pulse 324. The illumination source is deactivated in astep 310. The aiming pattern is activated in a step 312. Read out thestored image data values from the plurality of pixels is performed in astep 314 in response to a readout control timing pulse 326.

In an exemplary embodiment, the image reader utilizes the exposurecontrol timing pulse 324 to generate the aimer control timing pulse 320.For example, an image sensor manufactured by Micron Technology, Inc.having a product number MT9V022 provides a control signal output,labeled IMG_LED_OUT (see FIG. 14) which is a signal indicative of imagesensor exposure occurring. This signal can be utilized to control orprovide one or more of the aiming pattern, illumination, exposure andreadout control timing signals. For example, a transition of theIMG_LED_OUT signal could trigger a transition in the aiming controltiming signal after a predetermined time period or no time period toturn the aiming pattern LEDs off. Shortly thereafter, the illuminationand exposure control timing signals are programmed to transition to turnon the illumination LEDs to illuminate the target and start exposure ofthe image sensor. A subsequent transition in the illumination andexposure control timing signals to “off” would trigger a transition inthe readout timing control signal and possibly the aiming pattern timingcontrol signal, to turn the aiming pattern back on.

In an exemplary embodiment, the image processor 150 provides a timingcontrol signal which is utilized to control the aiming pattern (AIM_ON),illumination (ILL_ON), exposure IMG_EXP) and readout control timingsignals, as exemplified in FIG. 5 a.

In one embodiment the target is illuminated by overdriving theillumination sources, such as LEDs, to generate illumination severaltimes brighter than standard operation. According to this embodiment,the overdriven illumination sources in combination with the electronicglobal shutter allows for short exposure periods. That is, the brightillumination allows for a short integration time for each pixel and theglobal electronic shutter allows for all of the pixels in the imagesensor to be simultaneously exposed. With a short exposure period for abrightly illuminated target, an image reader of the present invention isable to collect a sharp non-distorted image even when the target ismoving relative to the image reader. In one embodiment, the exposureperiod is less than 3.7 milliseconds. In one embodiment in which thelight sources are overdriven, light sources with different colors areemployed. For example, in one such embodiment the image reader includeswhite and red LEDs, red and green LEDs, white, red, and green LEDs, orsome other combination chosen in response to, for example, the color ofthe symbols most commonly imaged by the image reader. In thisembodiment, the different colored LEDs are each alternatively pulsed ata level in accordance with the overall power budget. In another suchembodiment, both colored LEDs are pulsed each time but each at arelatively lower power level so that the over all power budget is againmaintained. In a further embodiment, red, green, and blue LED's can beinterleaved to simulate white light.

As noted, the process 300 includes processing the photoconversiongenerated electric charge to produce image data which can includeamplifying the data generated from the incident radiation and convertingthe generated data into a digital signal. The processing furtherincludes storing the generated image data values in a shielded portionof each of the plurality of pixels. The process 300 additionallyincludes reading out the stored image data values from the plurality ofpixels. The reading out of the plurality of pixels may be controlled bya readout timing control pulse which may include a plurality of pulsestransmitted to each of the plurality of pixels.

In an exemplary embodiment, the exposure control timing pulse beginsafter and finishes before the illumination control timing pulse. Thereadout control timing pulse begins at the conclusion of theillumination control timing pulse. In another embodiment, theillumination control timing pulse begins after and finishes before theexposure control timing pulse. In this embodiment, the readout controltiming pulse begins at the conclusion of the exposure control timingpulse. In further embodiments the exposure control timing pulse and theillumination control timing pulse overlap each other while occurringsequentially. In one such embodiment, this sequential operation caninclude the illumination control timing pulse starting, the exposurecontrol timing pulse starting, the illumination control timing signalpulse ending, and then the exposure control timing pulse ending. In thisembodiment, the readout control timing pulse begins at the conclusion ofthe exposure control timing pulse.

In an embodiment, the illumination source illumination control timingsignal pulse is coincident with the exposure control timing pulse, sothat the illumination LEDs are on only during the exposure period.Operating the illumination source in this manner reduces powerconsumption since the illumination source is on only during the exposureperiod thereby increasing battery life.

It should be understood that the programs, processes, methods andapparatus described herein are not related or limited to any particulartype of computer or network apparatus (hardware or software). Varioustypes of general purpose or specialized computer apparatus may be usedwith or perform operations in accordance with the teachings describedherein. While various elements of the preferred embodiments have beendescribed as being implemented in software, in other embodimentshardware or firmware implementations may alternatively be used, andvice-versa. The illustrated embodiments are exemplary only, and shouldnot be taken as limiting the scope of the present invention. Forexample, the steps of the flow diagrams may be taken in sequences otherthan those described, and more, fewer or other elements may be used inthe block diagrams. Also, unless applicants have expressly disavowed anysubject matter within this application, no particular embodiment orsubject matter is considered to be disavowed herein.

The claims should not be read as limited to the described order orelements unless stated to that effect. In addition, use of the term“means” in any claim is intended to invoke 35 U.S.C. §112, paragraph 6,and any claim without the word “means” is not so intended. Therefore,all embodiments that come within the scope and spirit of the followingclaims and equivalents thereto are claimed as the invention.

1. An apparatus comprising: a sensor array having rows of pixels whichare exposed to a target, wherein the sensor array generates a syncsignal; an aiming pattern generator for producing an aiming patternsuperimposed on the target; a processor which utilizes the sync signalto control the aiming pattern generator to: turn on the aiming patternduring exposure of a first predetermined row of pixels; turn off theaiming pattern during exposure of a second predetermined row of pixels;turn on the aiming pattern during exposure of a third predetermined rowof pixels; and, a housing for housing the sensor array, aiming patterngenerator and processor.
 2. An apparatus in accordance with claim 1,wherein the processor has memory and the processor stores identificationinformation of the first and second predetermined rows in the memory. 3.An apparatus in accordance with claim 1, further comprising memory whichstores identification information of the first and second predeterminedrows.
 4. An apparatus in accordance with claim 3, wherein the processorand memory are provided in the same integrated circuit package.
 5. Anapparatus in accordance with claim 1, wherein the processor counts thesync signal to determine the first and second predetermined rows.
 6. Amethod of reading a target with a hand held device comprising the stepsof: exposing a sensor array to the target, the sensor array having rowsof pixels; utilizing an on board processor for: turning on an aimingpattern superimposed onto the target during exposure of a firstpredetermined row of pixels; turning off the aiming pattern duringexposure of a second predetermined row of pixels.
 7. A method inaccordance with claim 6, wherein the processor has memory and furthercomprising the step of storing identification information of the firstand second predetermined rows in the memory.
 8. A method in accordancewith claim 6, further comprising storing in memory identificationinformation of the first and second predetermined rows.
 9. A method inaccordance with claim 8, wherein the processor and memory are providedin the same integrated circuit package.
 10. A method in accordance withclaim 8, wherein the utilizing step comprises counting the sync signalto determine the first and second predetermined rows.
 11. A method foroperating a hand held optical reading device comprising the steps of:projecting an aiming pattern onto the target; exposing one or more rowsof pixels in the image sensor; providing a plurality of row sync pulses;determining a row sync pulse count representative of each row of pixels;utilizing an on board processor for turning off the aiming pattern inresponse to a first predetermined row sync pulse count; and, turning onthe aiming pattern in response to a second predetermined row sync pulsecount.
 12. A method in accordance with claim 11, further comprising thestep of storing the first and second predetermined row sync pulse countin memory of a processor.
 13. A data reader for reading a targetcomprising: an aiming pattern source for projecting an aiming pattern onthe target; an illumination source for illuminating the target; a sensorarray for exposing an array of pixels to the target and for providing anexposure indication signal; wherein the exposure indication signal isutilized to turn off the aiming pattern source prior to exposure of thearray of pixels; and, a housing for housing the aiming pattern source,illumination source and sensor array for hand held operation.
 14. A datareader in accordance with claim 13, wherein the processor utilizes theexposure indication signal to turn on the illumination source.
 15. Amethod for reading a target comprising the steps of: superimposing anaiming pattern on the target; illuminating the target; exposing a sensorarray having an array of pixels to the target, the sensor arrayproviding an exposure control signal; utilizing the exposure controlsignal to turn off the aiming pattern source prior to exposure of thearray of pixels; and, housing the aiming pattern source, illuminationsource and sensor array in a common housing for hand held operation. 16.A method in accordance with claim 15, further comprising the step ofutilizing the exposure control signal to turn on the illuminationsource.
 17. An apparatus comprising: a sensor array having rows ofpixels which are exposed to a target, wherein the sensor array generatesa sync signal indicative of exposure of each pixel row; an aimingpattern generator for producing an aiming pattern superimposed on thetarget; a processor which utilizes the sync signal to control the aimingpattern generator to: turn on the aiming pattern during exposure of apredetermined row of pixels; turn off the aiming pattern after a firstpredetermined time after the aiming pattern is turned on; turn on theaiming pattern after a second predetermined time after the aimingpattern is turned off; and, a housing for housing the sensor array,aiming pattern generator and processor for hand held operation.
 18. Anapparatus in accordance with claim 17, wherein the processor has memoryand the processor stores identification information of the predeterminedrow in the memory.
 19. An apparatus in accordance with claim 17, furthercomprising memory which stores identification information of thepredetermined row.
 20. An apparatus in accordance with claim 19, whereinthe processor and memory are provided in the same integrated circuitpackage.
 21. An apparatus in accordance with claim 17, wherein theprocessor counts the sync signal to determine the predetermined row. 22.A method of reading a target with a hand held device comprising thesteps of: exposing a sensor array to the target, the sensor array havingrows of pixels; turning on an aiming pattern superimposed onto thetarget during exposure of a predetermined row of pixels; turning off theaiming pattern after a first predetermined time after the aiming patternis turned on; turning on the aiming pattern after a second predeterminedtime after the aiming pattern is turned off.
 23. A method in accordancewith claim 22, wherein the processor has memory and further comprisingthe step of storing identification information of the predetermined rowin the memory.
 24. A method in accordance with claim 22, furthercomprising storing in memory identification information of thepredetermined row.
 25. A method in accordance with claim 24, wherein theprocessor and memory are provided in the same integrated circuitpackage.
 26. A method in accordance with claim 24, wherein the utilizingstep comprises counting the sync signal to determine the predeterminedrow.
 27. An apparatus in accordance with claim 1, wherein the syncsignal is indicative of exposure of each pixel row.
 28. An apparatus inaccordance with claim 1, wherein the sync signal is comprised of atleast one of the following: exposure sync signal; vertical sync signal;horizontal sync signal; and, pixel clock signal.
 29. An apparatus inaccordance with claim 1, wherein the housing is adapted for hand heldoperation.
 30. An apparatus in accordance with claim 1, wherein thetarget is symbol indicia.
 31. An apparatus in accordance with claim 13,wherein the housing is adapted for hand held operation.
 32. An apparatusin accordance with claim 13, wherein the target is symbol indicia.